WASHINGTON (Reuters) - The U.S. Coast Guard is leading a search for two Marine helicopters carrying 12 people following reports they collided near the island of Oahu in Hawaii, a spokeswoman for the Coast Guard said on Friday.

The helicopters, each carrying six people, were reported to have collided just before midnight local time, spokeswoman Sara Mooers said.

Coast Guard crews have found debris in the waters but have not located any of the passengers, Mooers said.

The U.S. Navy and a local fire department is aiding the search, which has been hampered by dark, cloudy conditions and large waves, she said.

(Reporting by Susan Heavey, David Alexander and Laila Kearney; Editing by Bernadette Baum)